1. Saclay, 04 / 11 / 2002 E. Perez 1 Simulation of the performances of the upgraded L1Cal  Short reminder  Performances (jets) (see Jovan’s talk for electron studies)  Studies under way

2.  =0  =1  =4.5  =2 RunIIa L1 Cal  Level-1 calorimeter Trigger : u Run I Syst em (1990) u Unit = Trigger Tower (TT)  = 0.2  0.2  40  32  1280 EM + 1280 Had  Outputs : u # EM & EM+H TTs > 4 thresholds u Global Sums ( E T tot & missing E T ) Cal Preamp Precision Readout Trigger Pickoff Analog TT Sums BLS Card on detector ADC E  Et EM & EM+H Compare & Sums CTFE 4 EM + 4 H TT Sum / Add Trees

3. Expected problems with high Lumi  Size of a jet >> size of one TT (0.2 x 0.2) u Low thresholds, even to trigger on hard evts u Bad energy resolution u Slow rise of the trigger efficiency  bad background reduction  At L = 10 32 cm -2 s -1 : expected trigger rate with current menu > 5 kHz. Solution :  More selective L1Cal  

4. Saclay, 04 / 11 / 2002 E. Perez 4 “Sliding windows” algorithm Sliding sums of 2x2 Tower Triggers (RoI) Search for local maxima : comparison with neighboring RoI’s in an array 5x5 jet Energy = E in the 4x4 region (0.8 x 0.8 in  x  ) around the RoI      0.2  “jets” finder :  Also allows : Better ident. of electrons at L1 (isolation, transverse shape) Triggering on  (narrow jets) Including ICR at the trigger level cf LHC

5. Saclay, 04 / 11 / 2002 E. Perez 5 Simulation code  Sliding window algorithms implemented in a D0 package (tsim_l1cal2b)  Simulates jet, electron and global algos  Parameters : RoI size, declustering, size of the “jet” or “elec” region, isolation …  Used in Saclay & Nevis for simulation studies  Should be stable now … (bug in the noise treatment introduced at some point.. Corrected in september)  Jets : various algos studied & compared Similar performances  use “2,1,1”  Next : adapt to run the same code on data and MC

6. Saclay, 04 / 11 / 2002 E. Perez 6 Few simulation results  3 rate reduction Sharper turn-on curves Single Jet Reduction of trigger rates new current

7. Saclay, 04 / 11 / 2002 E. Perez 7 Performance on real data RMS / Mean : 23.8 % for (2,1,1) algo 53 % for current algo Using the “Moriond” J/  sample : Agreement with simulation Sharper turn-on curves

8. Saclay, 04 / 11 / 2002 E. Perez 8 Including ICR in trigger jets  Our “standard” files ( 7.5 mb ) : old version of d0sim wrong energies for TT’s in the ICR region  On more recent files : see the expected difference between with / without ICR The 7.5 mb files will be re-processed (p13) Meanwhile : can get a feeling of the effect Using the precision readout

9. Saclay, 04 / 11 / 2002 E. Perez 9 Including ICR in trigger jets Using the precision readout : Without ICR, using a  dependent Pt cut  Seems worthwhile to include ICR in the trigger jets Study to be finalized with p13 files

10. Saclay, 04 / 11 / 2002 E. Perez 10 Studies under way  Effect of the TT’s energy resolution on the trigger performances Currently : use 10% resol in the simulation Due to the digitisation step (0.25 GeV) no further improvement is expected when resolution becomes < xxx %  TT’s energy resolution on the data Compare energies seen by the trigger with precision readout Discussions (Jiri) with J. Kalk  know how to do  First look by Mathieu Agelou